This invention relates to a method of preventing peeling of paint. In a particular aspect, this invention relates to a method of preventing peeling of old paint from a substrate when a latex paint is applied over the old paint.
It is common knowledge that, when a latex paint, i.e., a water-based paint, is applied over an old oil-based paint on a substrate, ultimately extensive areas of the old paint will peel leaving the substrate bare. This occurs most frequently when a wooden house, fence, etc. which has been painted one or more times with an oil-based paint is painted with a latex paint. Initially the results appear to be satisfactory, but ultimately adhesion of the first coat fails and the entire coating peels.
This event has previously been regarded as the result of poor adhesion of the first coat. However, this explanation fails in view of the fact that adhesion was satisfactory until the latex coat was applied. Regardless of the cause, it was discovered that the problem could be minimized by applying an oil-based primer over the old paint before applying the latex. However, this solution suffers from the disadvantage that the old paint and substrate must be completely dry and free from moisture before the primer is applied, which is often difficult to achieve, especially on outdoor surfaces. Also, the oil-based primer lacks all the advantages of the water-based latex. Accordingly, there is a need for a better method of preventing peeling of old paint after application of a latex paint thereto.